The XResourceManagerString function returns the
RESOURCE_MANAGER property from the server's root window of screen zero,
which was returned when the connection was opened using XOpenDisplay.
The property is converted from type STRING to the current locale. The conversion
is identical to that produced by XmbTextPropertyToTextList for a single
element STRING property. The returned string is owned by Xlib and should
not be freed by the client. The property value must be in a format that
is acceptable to XrmGetStringDatabase. If no property exists, NULL is
returned.

The XScreenResourceString function returns the SCREEN_RESOURCES
property from the root window of the specified screen. The property is converted
from type STRING to the current locale. The conversion is identical to that
produced by XmbTextPropertyToTextList for a single element STRING property.
The property value must be in a format that is acceptable to XrmGetStringDatabase.
If no property exists, NULL is returned. The caller is responsible for
freeing the returned string by using XFree.